Annual security checks at nuclear power stations are not being carried out because of staff shortages caused by the 11 September terrorist attacks.
The first annual report by the Office of Civil Nuclear Security said that last year only nine out of 31 civil nuclear installations were fully inspected.
The agency, which is part of the Department of Trade and Industry, regulates security arrangements at civil nuclear sites. The inspections took place at four nuclear power stations, three separate facilities at Sellafield in Cumbria, and "two other sites".
The report, which covers October 2000 to March this year, said: "The programme had to be suspended immediately following the September terrorist attacks in the United States, to allow inspectors to concentrate their efforts on advising sites on the implementation of additional security measures."
Michael Buckland-Smith, director of the agency, said: "It is impossible, without a thorough and comprehensive programme of site inspections undertaken by experts, to identify security weaknesses or monitor compliance with standards and regulations.
"Due to staff shortages and other pressures, I do not expect to resume a full programme of inspections until next month at the earliest." However, he added: "On the other hand, site visits have been stepped up, so there has been no reduction in coverage." He said six new jobs are being created, although the report also said experienced staff were being lost to the private sector.
Pete Roach, a spokesman for Greenpeace, said: "One of the things they seemed to be having to do at nuclear sites is just look at plans for security rather than carrying out tests for security."
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